Swivel fittings for playground swings and the like



Dec. 26, 1961 E. c. LITTMANN 3,014,683

SWIVEL FITTINGS FOR PLAYGROUND SWINGS AND THE LIKE Filed Aug. 22, 1957 K\\ j INVENTOR.

ELLIS C. LITTMANN United States Patent Ofilice senses Patented Dec. 26, 196i.

3,014,683 SWIVEL FITTINGS FOR PLAYGRUUND SWINGS AND. THE LEKE Ellis C. Littmann, Clayton, Mo., assignor to Nixdortf- Krein Mfg. Co., St. Louis, Mo., a corporation of Delaware Filed Aug. 22, 1957, Ser. No. 6.795%! 2 Claims. (Cl. 24S21l) are, in turn, provided at their lower ends with a seatboard, hand-rings, or trapeze bar. Frequ ently,,the depending fittings are bolted to the tube and rigidly secured in position by means of a nut. However, during use, the depending fittings attached to the bar tend to become loose and to turn or twist out of proper alignment. This loosness or twisting will frequently impose added stresses on the fitting which cause it to pull open, so that the chain-supporting elements may actually drop oil, break or otherwise function improperly, resenting a serious safety hazard.

It is, therefore, one of the objects of the present invention to provide swivel fittings for rockably supporting swing chains, which fittings will remain snugly and nonrotatably in position on a horizontal bar or tube and will effectively resist abnormal stresses tending to pullthe fitting open. 7

It is another object of the present invention to provide a fitting of the type stated which will not become deformed during normal use of the swing, and, therefore, permits safe and trouble-free operation of the swing.

it is also an object of the present invention to provide a novel eyebolt and washer assembly adapted for use with playground swings and which permits rigid securement of the depending swing-chain supporting elements to a horizontal tube.

With the above and other objects in view, my invention nected by a horizontal pintle-portion 8, the section 7' being provided adjacent its end with an outwardly presented notch 9. Rockably mounted upon the pintleportion 8 is a swing hook it) including an upper eye portion 11 and a lower hook portion 12. Rotatably seated in, and extending through, the eye portion at for journahforming engagement with the pintle-portion 8 of the eyebolt 2 is a bushing 13 preferably formed of nylon or other similar plastic material. conventionally attached to the hook portions 12 are swing-chains 14, the lower ends of which are attached to a horizontal seatboard 15.

Interposed between the eye portion e and the tube 1 is a retention washer 16, the transverse contour of which is substantially in the form of a circular are having a radius slightly less than that of the horizontal tube 1. The washer to is centrally punched out in the provision of an elongated, somewhat rectangular, slot 17 defined by end margins 13, 19, which are longitudinally connected by straight parallel margins 26, 21, having spaced parallel depending ears 22, 23. The transverse distance between the margins 2d, 21, and also between the, opposed faces of the ears 22, 23, is slightly greater than the diameter of the wire or rod-stock used to fabricate the eyebolt 2, so that the eye 6 thereof will fit snugly and non-rotatably within the slot 17 and between the ears 22, 23. Similarly, the length of the slot 17 is approximately equal to the distance x across the upper portion of the eye 6 from. the bottom of the notch 59, as shown in FIG. 4. As seen by reference to FEGS. 3 and 4, when the nut 5 is drawn down tightly, the eye 6 of the eyebolt 2, will be p'ulledup snugly within'the slot 17 so that the ears 22, 23, are disposed snugly against the eye portion don either side thereof, and the notch 9 engages the end margin 13 of the slot 17. v The section 7 of the eyebolt 2 is seated snugly against the other end margin 19. It will, of course, be understood that the retention washer 16 is reversible with respect to the eyebolt 2 so that the notch 9 may equally well engage the end margin 1a, in which case the end margin 18 is engaged with the eye section 7.

resides in the novel-features of form, construction, ar'- rangernent, and combination of parts presently described and pointed out in the claims. 7

In the accompanying drawings:

FIG. 1 is a fragmentary front elevational view of a' childs swing equipped with swivel fittings constructed in accordance with and embodying the present invention;

shank 3, or, conversely, by rolling the out-size threads 4 onto the shank 3 after the washer 16 is in place.

in use, the shank 3 of, the bolt 2 is passed through the slot 17 so that the ears 22, 23, seat snugly against the eye portion 6, whereupon the shank 3 is pushed 1 through the tube 1 so'that its outer threaded end 4 ex- FIG. 2 is an eggplpded view of the eyebolt-washer as- I sembly forming a part of the present invention;

FIG. 3 is a fragmentary sectional view taken along line 33 of FIG. 1;

FIG. 4 is a sectional view taken along line ii-+4 of FIG. 3; and

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4.

Referring now in more detail and by reference characters to the drawings, which illustrate a preferred embodiment of the present invention, A designates a childs swing consisting of a hollow cylindrical horizontal bar ll drilled or punched for reception of eyebolts 2, each having a shank 3 which extends 'diametrally through the top bar 1. At one end, the shank 3 is provided with threads 4 for reception of a nut 5 which is adapted to bear against the outside of the tube 1. At its lower end,

tends outwardly of the tube 1. The nut '5 is then thread- Y ed onto the threaded end 4 and tightened down so as to draw the bolt 2, the retention washer i6, and the tube 1 into tightly assembled relation. The depending cars 22, 23, will then engage the sides of the eye 6 and prevent the latter from turning or twisting. Because the eye 6 cannot turn, the nut 5 will not tend to become loose, but, if, due to abnormal circumstances, the nut 5 should become slightly loose or possibly may not have been properly tightened up during installation, the ears dren will climb'onto the swing atone time and the 3 combined weight will impose an excessive downward load upon the eye 6. This load is, of course, increased with the square of the velocity as the children start to swing back and forth and, under such conditions, the eye of a conventional eyebolt will often pull open and fail, resulting in accidents. For some reason which is not immediately apparent, the provision of the notch 9 and the engagement thereof against the end margin 18 doubles the strength of the eyebolt 2 under the downward load conditions above described and this fact has been established by actual results in tensile-strength testing machines.

It should be understood that changes and modifications in the form, construction, arrangement, and combination of the several parts of the swivel fittings for playground swings and the like may be made and substituted for those herein shown and described without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In combination, a cylindrical support bar having a relatively large opening extending therethrough, a retention washer having a generally cylindrical contour and being adapted to fit snugly and non-rotatably against the outer face of the support bar, said washer being provided with an axially elongated slot which is shorter in length than the axial dimension of the opening, and a swing eyebolt having a shank inserted through said opening and provided at one end with a substantially triangular eye consisting of first, second and third straight sections, the first straight section being integrally connected at one end to the shank and at its other end to one end of the second straight section and extending angularly outwardly from the shank, said second straight section being, in turn, integrally connected at its other end to one end of the third straight section, said third straight section extending angularly inwardly toward the shank and terminating in a free end located in close proximity to the region of integral juncture between the first straight section and the shank, thereby forming a narrow apexportion which is shorter in length than the slot and will fit up into said slot, the second straight section being of substantially greater length than the slot in the retention washer and being adapted, when in operative position, to extend in outwardly spaced parallel relation to said slot, said triangular eye being provided, in the region of said apex-portion, with a laterally opening indented recess having an outer lip and a bottom surface, the transverse distance across the eye between said lip and the outer surface of the third straight section being smaller than the axial length of the slot, the transverse distance between the bottom surface of the recess and the outer surface of the first straight section being substantially equal to the axial length of the slot so that when the eyebolt is inserted through the slot the lip will initially pass through the slot and then be shifted laterally as the triangular eye becomes fully seated in the slot whereby the recess becomes retentively engaged with a transverse margin of the slot.

2. In combination, a cylindrical support bar having a relatively large opening extending therethrough, a retention washer having a generally cylindrical contour and being adapted to fit snugly and non-rotatably against the outer face of the support bar, said washer being provided with an axially elongated slot which is shorter in length than the axial dimension of the opening, and a swing eyebolt having a shank inserted through said opening and provided at one end with a substantially triangular eye consisting of first, second and third straight sections, the first straight section being integrally connected at one end to the shank and at its other end to one end of the second straight section and extending angularly outwardly from the shank, said second straight section being, in turn, integrally connected at its other end to one end of the third straight section, said third straight section extending angularly inwardly toward the shank and terminating in a free end located in close proximity to the region of integral juncture between the first straight section and the shank, thereby forming a narrow apexportion which is shorter in length than the slot and will fit up into said slot, the second straight section being of substantially greater length than the slot in the retention washer and being adapted, when in operative position, to extend in outwardly spaced parallel relation to said slot, said triangular eye being provided, in the region of said apex-portion, with a laterally opening indented recess having an outer lip and a bottom surface, the transverse distance across the eye between said lip and the outer surface of the third straight section being smaller than the axial length of the slot, the transverse distance between the bottom surface of the recess and the outer surface of the first straight section being substantially equal to the axial length of the slot so that when the eyebolt is inserted through the slot the lip will initially pass through the slot and then be shifted laterally as the triangular eye becomes fully seated in the slot whereby the recess becomes retentively engaged with a transverse margin of the slot, said washer being integrally provided with outwardly projecting ears extending along the longitudinal margins of the slot so as to bear against the sides of the triangular eye and prevent the eyebolt from turning.

References Cited in the file of this patent UNITED STATES PATENTS 441,473 Drivall Nov. 25, 1890 1,088,105 Sharp Feb. 24, 1914 1,124,890 Green Jan. 12, 1915 1,321,742 Hendricks Nov. 11, 1919 1,580,015 Clark Apr. 6, 1926 2,613,422 Boden Oct. 14, 1952 2,625,357 Atkinson Jan. 13, 1953 2,662,571 Kessler Dec. 15, 1953 2,789,871 White Apr. 23, 1957 2,867,874 Larson Jan. 13, 1959 2,900,160 Hammond Aug. 18, 1959 

